A Monstrous Spider egg is pale orange in color, and is normally in a silken "purse" with hundreds of other eggs. The size of the egg varies depending on the size of its mother (see the "size" column on Table: Monstrous Spider Eggs). Monstrous Spider Eggs can be bought from some black market stalls in cities and are also commonly found in Drow markets.

A Spider Rider's egg does not follow the rules presented here for monstrous spider eggs. Spider Riders get their spider eggs as a gift from their deity (and thus do not need to buy an egg). A Spider Rider cannot use a "bought" Monstrous Spider Egg to fulfill the prerequisites of the prestige class.

A monstrous spider egg hatches 2D10+52 days after the mother lays it. The size of the spiderling is shown in Table: Monstrous Spider Sizes in the "size" column. If the egg is still in the silken purse it cannot get out unless the purse is split in some way. It can be split by its mother or naturally.

A spiderling grows in size until it is the same size as its mother (see spider size column in Table: Monstrous Spider Eggs). The spiderling increases by one size category about 5 months after it hatches. It then grows one size category about once every two months thereafter.